Chasing the effects of dust deposition on coccolithophores living across the Atlantic Ocean
Over the past two years, a team of young researchers from MARE-UL embarked on two AMT expeditions, as part of a PORTWIMS training programme. Amongst other assignments, Andreia Tracana, Afonso Ferreira, Giulia Sent and Carolina Sá oversaw daily sampling of atmospheric dust and plankton for the study of coccolithophores thriving along the entire photic zone. The goal was to further explore the link between dust-born nutrient deposition in the Atlantic Ocean and the productivity, composition and distribution of this biogeochemically important group.
Top left: Andreia filtering seawater for the the study of coccolithophore communities; bottom left: Catarina using a polarizing light microscope for coccolithophore taxonomy; right: Guila and Andreia preparing the atmospheric dust collector.
These samples are now being analysed as part of a new project - CHASE (CHASing the environmental Effects of dust deposition across the Atlantic and Southern Ocean: a coccolithophore perspective), which is led by MARE-ULisbon in close collaboration with Instituto Dom Luiz (IDL), Plymouth Marine Laboratory (PML), Royal Netherlands Institute for Sea Research (NIOZ) and East Anglia University (EAU).
The microscopic analysis for the taxonomic identification of coccolithophores is well underway, thanks to Catarina Pinto, an MSc student from the University of Aveiro (Portugal). Catarina is doing her MSc research on “Coccolithophores (Haptophyte) living in the North Atlantic (50° – 30°N): results from AMT28”. So far, she has done a terrific job at learning the taxonomy of the group during such strange pandemic times, providing the first pictures of some of the beautiful coccospheres that we found on the plankton samples. Her next step will be undertaking a detailed multi-proxy exploration of all the gathered ecological data in synergy with a wide range of remote-sensing time-series observations.
Project CHASE, funded by the Portuguese Science Foundation, is closely intertwined with PORTWIMS and a follow-up study from the recently completed EU-H2020 project DUSTCO (www.dustco-online.com). Both DUSTCO and CHASE are projects based on the premise that atmospheric dust deposition is likely to change the Earth’s climate and atmospheric CO2 through fertilizing the ocean (nutrient source) and by accelerating the biological carbon pump (ballasting effect).
Some images illustrating the beautiful coccolithophore species diversity found in the North Atlantic.
DUSTCO already provided relevant evidence on the increasing importance of deep-dwelling coccolithophores Florisphaera profunda and Gladiolithus flabellatus in response to ongoing climate driven ocean warming. As these species are typically more abundant in highly stratified and oligotrophic tropical conditions, recent observations suggest that they might have a competitive ecological advantage in a future warmer ocean. Data further indicate that this ecological change is likely to contribute to weaken the biological carbon pump thorough increasing the “rain ratio” and reducing the efficiency of coccolith-ballasting. Such tendency may, however, be at least partially counterbalanced by increasing Saharan dust outbreaks across the Atlantic acting as a fertilizer to fuel fast blooming coccolithophore productivity as well as increasing their efficiency as ballasts. In addition to dust, discharge and dispersal of Amazon water, as well as seasonal deepening of the mixed layer revealed to also significantly promote primary production and subsequent export and sequestration of organic carbon in the tropical North Atlantic.
CHASE will expand existing knowledge on the transatlantic export productivity of coccolithophores gained from DUSTCO towards an environmentally broader perspective, spanning tropical, subtropical, temperate, subpolar and polar waters across the entire Atlantic Ocean and Southern Ocean. The project will also explore the potential effects from other sources of dust besides the Saharan desert and the Sahel region. The overall goal is to use a holistic and multidisciplinary approach to advance existing knowledge on the link between atmospheric, oceanographic, ecological and biogeochemical processes involved during the outburst of dust storms over and into the Atlantic, and its effects on the biogeochemically important coccolithophores.
PORTWIMS Coordinator, Vanda Brotas, is featured on a radio programme which aims to make the science of Portugal better known and understood in just 90 seconds.
In her broadcast Vanda talks about how her group of researchers at the University of Lisbon are using satellites to study phytoplankton, the microscopic plants which are responsible for producing half of all the global oxygen.
New project success - CERTO
The Copernicus Marine, Climate Change & Land services all produce EO-based water quality data using different methods for ocean, shelf waters and lakes, while none cover transitional waters. A new EC H2020 project, CERTO, aims to harmonize methods across the services, develop specific methods for transitional waters and develop indicators relevant to stakeholders. CERTO brings further collaboration between PML & the University of Lisbon, as well as 8 other partners, & demonstrates the value of PORTWIMS for promoting the university's involvement in more projects.
For further information please see www.certo-project.org
Lisbon scientists sail the Atlantic
Three early-career researchers, Andreia Tracana (left), Guilia Sent (centre) and Carolina Sa' (right), from the University of Lisbon are participating in the 29th Atlantic Meridional Transect cruise. Here they can be seen alongside RRS Discovery in the Azores.
Carolina has spent time training at PML and preparing for the cruise and is now on board the ship operating a hand-held sun photometer to obtain measurements of atmospheric aerosols. She is working in collaboration with NASA and the information will be crucial to validate satellite measurments of aerosol properties as these measurements are scarce in the open ocean.
Guilia, an MSc student, is using microscopy and high-performance liquid chromatography to characterize phytoplankton communities in the the Atlantic Ocean and Andreia is participating in AMT for the second time to investigate the effects of Saharan dust on coccolithophore communities.
An international team of young researchers on board the Polarstern
Mara Gomes from MARE-FCUL is participating in a month long expedition from the Falkland Islands to Bremerhaven, the South-North Atlantic Training Transect cruise as part of PORTWIMS. They are part of a team of 25 young scientists who will gain unique insights into the marine sciences and engage in short projects on interactions between the ocean, atmosphere and climate.
See the press release or cruise blog for updates.
YouTube video on Earth Observtion
Vanda Brotas participated on a conference included on the program CCOceanos 2019 – sponsored by Vodafone, on the 14th February 2019, where she highlighted the importance of PORTWIMS for the development of expertise on Earth Observation in Portugal. This programme consists of a set of conferences for the general public, which are recorded and streamed in Portuguese.
PORTWIMS objectives presented at the Atlantic4Space workshop
Vanda Brotas gave a presentation in January 2019 at the Atlantic4Space Workshop in Southampton, UK titled "Survey of Earth Observation activities conducted at the University of Lisbon on the Northeast Atlantic" which included presentation of the PORTWIMS main objectives.
Download the slides from the presentation.
Applications for PORTWIMS Summer Schools now open
"The girl who could see the sea with different colours" by Vanda Brotas
On 1st December, Vanda Brotas launched a Portuguese children’s book “The girl who could see the sea with different colours”, which aims to call the attention of 8-11 years old to the role of phytoplankton in the marine ecosystem and the way Earth Observation satellites work. The book is published by Gradiva. The book is sponsored by Ciência Viva which is the major Portuguese Governmental Agency in Science Communication and Outreach.
* Update - the book has now been translated and is available to download in an English version *
Vanda used her book to explain to 10-12 year old students what is the colour of the ocean during a school visit in March 2019. She used the book to help explain what phytoplankton is, it's importance and how satellites can observe the colour of the ocean.